1. Field of the Invention
The present invention relates to managing diabetes symptoms, and more particularly, to a device and method for controlling diabetes symptoms and monitoring a diabetes patient.
2. Description of Related Art
The prior art includes devices for monitoring blood glucose levels of diabetes patients and devices for administering insulin to control blood glucose levels. Known blood glucose monitors take many forms. For example, one type of monitor is implanted in a patient and transmits blood glucose readings to an external display more or less continuously. Other devices require the patient to take periodic blood samples for analysis by the glucose monitor. In the latter type of device the patient typically lances a finger and places a blood sample on a medium such as a test strip. The monitor analyzes the test strip and provides a digital readout of the blood glucose level on a monitor display.
Depending on the patient's blood glucose level, it may or may not be necessary to administer a dose of insulin. Insulin delivery devices also take many forms. Broadly speaking, insulin delivery can be either essentially automatic by permanently attaching the patient to an insulin pump, or as-needed by using an injection device (such as a hypodermic needle) with which the patient injects an amount of insulin determined according to a predetermined protocol when the measured blood glucose level is outside an acceptable range.
Many devices and systems seek to automate diabetics' blood glucose control protocols by computerizing conventional devices so that insulin dosages can be automatically determined and delivered with minimum intervention by the patient. The following references illustrate some typical examples of such devices and systems:
U.S. Pat. No. 4,731,726U.S. Pat. No. 5,019,974U.S. Pat. No. 5,536,249U.S. Pat. No. 5,593,390U.S. Pat. No. 5,728,074U.S. Pat. No. 5,822,715U.S. Pat. No. 5,840,020U.S. Pat. No. 5,925,021U.S. Pat. No. 6,192,891U.S. Pat. No. 6,544,212U.S. Pat. No. 6,875,195U.S. Pat. No. 6,906,802U.S. Pat. No. 7,427,275U.S. Pat. No. 7,534,230U.S. Pat. No. 7,591,801U.S. Publ. No. 2008/0306434U.S. Publ. No. 2010/0010330European. App. No. 1 102 194
Devices disclosed in U.S. Pat. No. 5,728,074 embody the “as-needed” type of insulin delivery approach. Some of these disclosed devices could be particularly useful because they provide a variety of functions that a diabetic would undoubtedly find helpful in managing his or her disease. For example, the disclosed embodiments include devices that combine an insulin injection mechanism and a blood glucose monitor, such as the “pen-type injector” depicted in FIG. 25. This device has at one end a removable cap that conceals a hypodermic needle for insulin injection and a lancet mechanism used by the patient to prick a finger to obtain a blood sample for analysis by a test strip on the injector housing. U.S. Patent Pub. No. 2010/0010330 exemplifies the type of system that employs a blood glucose sensor implanted in the patient to provide continuous glucose level data to a bedside monitoring system that controls an insulin infusion pump. The system can include software that determines if the patient's blood glucose level is at a dangerously low level and can alert 911 or other medical emergency response provider. While this feature enhances patient safety, it has a significant drawback in that the patient is tethered to the monitoring system.
Many diabetics lead relatively active lives, and for them being tethered to a monitoring system is obviously not acceptable. These patients require a treatment regimen that enables them to maintain a normal lifestyle by minimizing limitations that might otherwise be imposed by their diabetes. Even though existing devices and systems permit such patients to closely monitor their own blood glucose levels, and thus minimize the risk of becoming hypoglycemic or hyperglycemic at any given time, a diabetes patient still can experience either condition without much warning. Hypoglycemia can be particularly dangerous because it can impair cognitive functions, so a patient with a low blood glucose level can become disoriented and confused very rapidly. If the patient's blood glucose level is not corrected in time, he or she can lapse into a coma and even die before being able to take necessary corrective action. By the same token, hyperglycemia, while less likely than hypoglycemia to present an emergency situation, can nonetheless be dangerous. Accordingly, devices that rely on the patient to take appropriate steps after determining his or her own blood glucose level would have greater utility if they could automatically take action to preempt the potentially serious consequences of rapid changes in blood glucose levels.